Combining Philosophers

All the ideas for Aeschylus, Euclid and Jan Westerhoff

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27 ideas

2. Reason / E. Argument / 6. Conclusive Proof
Proof reveals the interdependence of truths, as well as showing their certainty [Euclid, by Frege]
4. Formal Logic / C. Predicate Calculus PC / 2. Tools of Predicate Calculus / c. Derivations rules of PC
If you pick an arbitrary triangle, things proved of it are true of all triangles [Euclid, by Lemmon]
5. Theory of Logic / F. Referring in Logic / 1. Naming / a. Names
We negate predicates but do not negate names [Westerhoff]
6. Mathematics / A. Nature of Mathematics / 2. Geometry
Euclid's geometry is synthetic, but Descartes produced an analytic version of it [Euclid, by Resnik]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / b. Types of number
An assumption that there is a largest prime leads to a contradiction [Euclid, by Brown,JR]
6. Mathematics / A. Nature of Mathematics / 3. Nature of Numbers / m. One
A unit is that according to which each existing thing is said to be one [Euclid]
6. Mathematics / A. Nature of Mathematics / 5. The Infinite / a. The Infinite
Postulate 2 says a line can be extended continuously [Euclid, by Shapiro]
6. Mathematics / B. Foundations for Mathematics / 3. Axioms for Geometry
Euclid relied on obvious properties in diagrams, as well as on his axioms [Potter on Euclid]
Euclid's parallel postulate defines unique non-intersecting parallel lines [Euclid, by Friend]
Euclid needs a principle of continuity, saying some lines must intersect [Shapiro on Euclid]
Euclid says we can 'join' two points, but Hilbert says the straight line 'exists' [Euclid, by Bernays]
Modern geometries only accept various parts of the Euclid propositions [Russell on Euclid]
6. Mathematics / B. Foundations for Mathematics / 5. Definitions of Number / b. Greek arithmetic
Euclid's common notions or axioms are what we must have if we are to learn anything at all [Euclid, by Roochnik]
7. Existence / E. Categories / 1. Categories
How far down before we are too specialised to have a category? [Westerhoff]
Maybe objects in the same category have the same criteria of identity [Westerhoff]
Categories are base-sets which are used to construct states of affairs [Westerhoff]
Categories are held to explain why some substitutions give falsehood, and others meaninglessness [Westerhoff]
Categories systematize our intuitions about generality, substitutability, and identity [Westerhoff]
Categories as generalities don't give a criterion for a low-level cut-off point [Westerhoff]
Categories can be ordered by both containment and generality [Westerhoff]
7. Existence / E. Categories / 2. Categorisation
The aim is that everything should belong in some ontological category or other [Westerhoff]
7. Existence / E. Categories / 3. Proposed Categories
All systems have properties and relations, and most have individuals, abstracta, sets and events [Westerhoff]
7. Existence / E. Categories / 5. Category Anti-Realism
Ontological categories are like formal axioms, not unique and with necessary membership [Westerhoff]
Categories merely systematise, and are not intrinsic to objects [Westerhoff]
A thing's ontological category depends on what else exists, so it is contingent [Westerhoff]
9. Objects / D. Essence of Objects / 5. Essence as Kind
Essential kinds may be too specific to provide ontological categories [Westerhoff]
25. Social Practice / D. Justice / 2. The Law / b. Rule of law
The 'Eumenides' of Aeschylus shows blood feuds replaced by law [Aeschylus, by Grayling]